New York City is facing an environmental crisis that is threatening not only our prestige and competitiveness, but also our quality of life. And it is costing New Yorkers — both property owners and tenants — a lot of money.

The issue is our buildings: They are huge consumers of energy and breeding grounds for greenhouse gases. Each year, buildings emit more harmful carbon dioxide (CO2) emissions into the environment than our cars do.

I don't mean just single-family homes, with their famously leaky windows and lack of proper insulation, but offices, apartment buildings, warehouses and factories of all types and sizes. NYC buildings may have been state-of-the-art at one time, but when you look at these structures today, from an environmental perspective, the scorecard changes dramatically.

Consider this: On average, New Yorkers are paying among the highest energy rates in the country, which drive $15 billion of energy bills for our buildings each year.

Almost 80 percent of CO2 emissions in NYC come from heating, cooling and providing electricity to buildings. That's more than double the national average. At the rate and pace we're going, our energy costs will continue to rise as we experience the effects of climate change, including more heat waves, an increasing number of floods and storms, and more energy blackouts.

How should New Yorkers respond?

One way to start is to urge quick passage of a package of green building legislation that is being considered by the New York City Council. The bills, introduced as part of Mayor Bloomberg's environmental greenprint called PlaNYC, will require improvements in more than 20,000 city buildings to lower emission levels and increase energy efficiency. They will also create thousands of new construction jobs for the development of green buildings. The energy improvements would be financed with funds from the American Recovery and Reinvestment Act (ARRA).

Technology can help, too. Everything from temperature, electricity and ventilation to water, waste management, telecommunications and physical security within a building can be integrated for better management and control. Low-cost sensor technology, programmable thermostats, video cameras and other devices have made it much easier to monitor these functions. But in very few cases are we using analytic intelligence to make the best use of all the data we are collecting.

When it comes to energy efficiency, it's hard to top the new 7 World Trade Center, which opened in 2006. The 52-story tower, New York City's first green building, has earned leadership recognition from the Environmental Protection Agency, the U.S. Green Building Council, and others. It has computer-controlled systems to heat and cool the tower, high-efficiency plumbing systems, a filtration system to improve indoor air quality, and a water conservation system to harvest rainwater for cooling and for irrigation. Devices such as carbon dioxide sensors, daylight dimming controls, variable speed fans, and steam-to-electricity turbine generators help reduce energy costs. Electricity costs are about 35 percent lower than in a conventional building and water consumption is about 30 percent lower.

But most of our energy consumption and carbon dioxide emissions come from older buildings. So we need to retrofit existing buildings with energy-efficient systems that are instrumented, interconnected and intelligent.

A good example of retrofitting is the Perry Avenue Building, one of the nation's first multi-story green industrial facilities, which opened in Brooklyn Naval Yard earlier this year. It combines wind turbines, rooftop solar panels and reflective roofing to reduce surface temperatures. Rainwater is recycled in the toilets, and there are even special accommodations for low-emission vehicles. And its functions are integrated, managed and monitored with technology.

Seven World Trade Center and the Perry Avenue Building are just a start. NYC needs many more environmentally sustainable buildings to rein in our energy costs and lower CO2 emissions from our buildings. ARRA has given us a once-in-a-lifetime opportunity to invest in projects that will have long-term economic and societal benefits. We need to move quickly to make our buildings ... public and private ... existing and future ... as efficient and high-performance as they can be. Our well-being and competitiveness as a global city depend upon it.

Paul M. Horn has been a Distinguished Scientist in Residence at NYU since 2007. He lectures and conducts research at the Stern School of Business, the Courant Institute of Mathematical Sciences and the Graduate School of Arts and Science. Horn led IBM's $5 billion research and development division for more than a decade, retiring in July 2007. A physicist by training, he led a major shift to more energy-efficient computing and directed high-profile projects, including IBM's Deep Blue supercomputer that beat Kasparov in chess; the world's first copper chip; and Blue Gene, the world's first petaflop computer — 10 times more powerful than any previous computer.